This is a multidisciplinary investigation of the vascular neuroeffector mechanism in health and disease; specifically, its normal functioning, development and regulation, variation in specific regional beds and alteration in hypertension. It includes the following specific projects: The heterogeneity of the blood vessel wall; the functional significance of neurogenic beta-adrenergic receptor vasodilation; the distribution of innervation density among arteries and veins; the functional and structural changes in a rabbit artery that follow sympathectomy; the specificity of re-innervation of blood vessel transplants; the species varriation in the neurogenic control of the cerebral circulation; the transient and persistent changes in blood vessels associated with a prolonged elevation in arterial pressure; elevated tonic sympathetic activity; and the characterization of the neuroeffector status of omental vessels removed from patients with primary hypertension.